Method and apparatus for insuring that the transport of a scanning system is contiguous with its support

ABSTRACT

The transport, that carries the material to be scanned to and from scanning position, is held against its support by suction. After the transport has been moved into scanning position the suction is applied progressively starting at one end of the transport and continuing to the other end. A squeegee roller presses the transport against its support. This roller passes over the portion of the transport to which suction has just been applied, but prior to the time that suction is applied to the next section of the transport.

TECHNICAL FIELD

This invention relates to scanning systems; and more particularly tofirmly securing the transport, that carries the material to be scanned,in its proper place.

BACKGROUND ART

Prior to our invention, Ernest M. Rossini invented the broad inventionof moving the transport of a scanning system from its normal flatposition, on a table, to a position contiguous with a curved inner wallof the scanning system. Rossini's invention involved holding thetransport against the curved inner wall by suction. His invention isclaimed in his application Ser. No. 384,366, filed on even dateherewith, entitled: Method of and Apparatus for Feeding and PositioningMaterial to be Scanned.

DISCLOSURE OF INVENTION

We have invented improvements upon the basic concept of Rossinidescribed above. We invented the improvement of progressively applyingsuction along the transport to hold it against the curved inner wall. Wealso invented the further improvement of applying pressure along thetransport; relying on a squeegee roller for this purpose. This rollermoves along the transport, and presses each portion of the transportagainst its support while the suction is applied to such portion.

RELATED APPLICATIONS

In addition to the prior invention of Rossini, described above, thefollowing inventions of others are shown and described in thisapplication.

Certain improvements in the rotatary scanning system (see FIG. 2 of thisapplication) are described and claimed in the application of Joseph J.Crane and Daniel T. Beasley, Ser. No. 383,930, filed on even dateherewith, and entitled: "Scanning System Employing a Laser Beam."

Improvements in the means for rotating and laterally moving the scanningdevice are described and claimed in the application of Joseph J. Crane,Ser. No. 383,928, filed on even date herewith, and entitled: "ScanningWherein the Scanning Beam Rotates and Translates." These improvementsare shown in FIGS. 3 and 4 of this application.

An improved table and method, for feeding the transports to, andreceiving and transports from, the scanning system are disclosed inapplications of Wah Sheck, Ser. Nos. 383,927 and 383,929, filed on evendate herewith and respectively entitled: "Method of Feeding Material Toand Receiving it From a Scanning System," and "Apparatus for FeedingMaterial To and Receiving Material From a Scanning System." Theimprovements described and claimed in the Sheck applications are shownand described in connection with FIGS. 13 to 15 of this application.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view, partly schematic and partly perspective, of a scanningand feeding device embodying the invention.

FIG. 2 is a cross-sectional view of the rotating scanning means and thehousing therefor.

FIG. 3 is a side view of the scanning device and shows the means formoving the scanning device laterally.

FIG. 4 is a top view of the means for moving the scanning devicelaterally.

FIG. 5 is a view partly in cross-section, of the rotating scanningdevice and its housing.

FIG. 6 is a top view of a transport for carrying the materials to bescanned to the scanning system.

FIG. 7 is a cross-section, of registration pin (159) and its support,taken along line 7--7 of FIG. 6.

FIG. 8 is a top view of a transport for performing the same function asthe transport of FIG. 6, except it shows certain modified forms of tapesfor holding the materials to be scanned.

FIG. 9 is a detailed view of a portion of FIG. 8.

FIG. 10 is another detailed view of a portion of FIG. 8.

FIG. 11 is a detailed view of still another portion of FIG. 8.

FIG. 12 is a detailed view of yet another portion of FIG. 8.

FIG. 13 is a top view of a table for holding a transport. This figure iscomposed of four sub-figures 13A, 13B, 13C and 13D which should be puttogether as shown in FIG. 21 to show FIG. 13.

FIG. 14 is a rear view of the table (FIG. 13) for the transport. Thisfigure is composed of two sub-figures which are to be put together toproduce FIG. 14.

FIG. 15 is a right side view of the table (FIG. 13) for the transport.The two parts of this figure are to be put together along the match line

FIG. 16 is a left side view of the Table (FIG. 13) and its associateddoor.

FIG. 17 shows a disc inside the drum together with means for positioninga transport in the drum (243)

FIG. 18 shows further details of the means in the drum for positioning atransport.

FIG. 19 is an exploded view of certain details of FIG. 1.

FIG. 20 is a cross-sectional view along line 20--20 of FIG. 1.

FIG. 21 shows how the sub-drawings 13A, 13B, 13C and 13D are puttogether to form FIG. 13. It also shows how sub-drawing 14A and 14B formFIG. 14.

BEST MODE FOR CARRYING OUT THE INVENTION

Before describing the overall machine in detail, a very briefdescription of it will be given with reference to FIG. 1.

FIG. 1 is an overall schematic of the scanning device for reading and/orwriting using laser beams.

A cylindrical drum section (243), having side walls (244), carriessupport member (131) which in turn supports cradle (130) which in turnsupports the housing (101), which contains a rotating element (120) withmirrors for reflecting the laser beams onto the materials to be readand/or written upon. The mirrors provide scanning and, therefore, bothrotate and translate. The rotary motion is achieved by virtue of aturbine (118) (FIG. 2) which is operated by compressed air fed into thehousing (101). The turbine (118) rotates the rotating elements (120).Linear motion of the elements (120) is provided by the lead screw (133),which is rotated by a stepping motor (136), (shown in FIG. 3), and whichpasses through the internally threaded housing (138) attached to thesupport (131) by clamp (139). The lead screw (133) is supported bybearings (134) located in casings (140) and (141).

The reading and/or writing material is placed on a transport (150) (FIG.6) which is placed on bed (191) in front of bar (192) (FIG. 1). When itis desired to move the transport (150) (FIG. 6), carrying the materialsto be read and/or to be written upon, into the drum (243), the bar (192)is moved forwardly a short distance which causes the transport plate(150) to pass to a group of pinch rollers (one of which (202) is shownin FIG. 1). These rollers drive the transport (150) into drum (243) aswill be more fully explained. A second transport (150) carryingadditional spaces for reading and writing may be placed on two L-shapedbrackets, one of which is shown in FIG. 1 and bears reference number(195). A similar L-shaped bracket is provided on the opposite side ofthe apparatus as more fully explained in connection with FIG. 13. Afterthe first transport (150) has been fed into the drum (243) for thepurposes of reading and/or writing, the second transport (150) may bedropped upon the bed (191) by rotating the bracket (195) and itscorresponding bracket on the other side of the machine. The secondtransport (150), therefore, drops by gravity on the bed (191) and hasthe material for scanning placed on it. After reading and/or writing hasbeen accomplished on the first transport (150) that was sent into thedrum (243), the air is exhausted from cylinders (200) to lower bed (191)so that the horizontal section of brackets (195) (and its correspondingbracket on the other side of the machine) are at the level to receivethe first transport (150) that was previously fed into the machine. Thematerial in the reading and writing sections of the first transport(150), may, therefore, be changed to provide a new page for thenewspaper after the second transport (150) has been loaded and the firsttransport (150) dropped. The cylinders (200) must be placed under airpressure, or relieved of air pressure, as necessary to correctlyposition the bed (191) and brackets (195, 197) (FIG. 13). When atransport (150) is to be fed into the drum (243), the bed (191) is inits raised position and when the brackets (195, 197) are to receive atransport (150) from the drum (243), the bed (191) is in its lowerposition.

As will appear, a vacuum is desirable in order to hold the transport(150) in place in the drum (243), during scanning, and, therefore, avacuum pump (248) is provided.

A guiding ramp (249) is provided between the bed (191) and the drum(243) so that the transport may pass along this ramp when passing to andfrom the drum (243).

The bearing (100) is supported by the housing (101) which as we shallsee, moves laterally and parallel to the material to be scanned, butdoes not rotate about the axis (109) of FIG. 2. The shaft (102) rotates,with reference to the bearing (100) and the housing (101), around theaxis (109). Air under pressure from 80 to 100 pounds per square inch isconnected to input (103) and enters an annular slot (105) whichcompletely encircles the outer portion of bearing (100). The air underpressure also enters annular trough (104) through holes (1030), to thusprovide an air bearing surface between the rotating shaft (102) and thebearing (100). This air space (106) between bearing (100) and shaft(102), is approximately 0.0008 inches wide. The air is slowed along thegap (106) between bearing (100) and shaft (102) by seals (107) which areof annular shape leaving a gap of 0.0004 inches and are preferably madeof a material known as Vespel manufactured by DuPont. The O rings (108)prevent leaking of the air passing inlet (103) to the annular groove(104). The cap (110) is connected to the housing (101) and has a vent(111) which feeds hole (1110) (FIG. 20), whereby any air which leakspast seal (107) is vented to the atmosphere. Some air from the gap (106)also passes seal (107) to space (113) which is at lower pressure, aswill be seen, than the pressure in gap (106).

Air under pressure from a servo mechanism that controls the air pressure(see part 142 in FIG. 5) enters inlet (114) to the spaces (116), andthen via air ports (115) to the ports (117) to drive the turbines (118).The turbines rotate the endplates (119) which in turn rotates opticalhousing (120) which carries with it the mirrors (121) and the lens(122), both of which, therefore, rotate at the same speed as theturbines (118).

Air under pressure at about 40 lbs. per square inch is also fed into theannular groove (123) from which air under pressure passes slowly throughthe bronze porous plate (124) and applies pressure to the flat innersurface (125) of the turbine (118). An air gap of approximately 0.003 to0.005 inches is provided between the porous plate (124) and the platewhich comprises the end surface (125) of the turbine (118.)

Heretofore, devices with rotary air bearings have been used, not only inconnection with scanning devices of the general class involved here, butalso in other applications. One problem that has arisen in connectionwith such air bearings is that there is unwanted lateral movementbetween the housing and the rotating part. Such unwanted lateralmovement is very objectionable in the case of a scanning device of thecharacter involved here because any lateral error in the position of themirrors (121) will cause an error in the materials being read and/orprinted as the case may be. This lateral movement which causes sucherror is avoided, in accordance with this invention, by reason of theporous bronze plate (124) at both ends of the device. Air under pressureenters the annular cavities (123), both at the right end of the devicevia feed line (1230) and at the left end of the device via feed line(1231), and passes slowly through the porous bronze plates (124) andapplies pressures on the flat surfaces (125) of the turbines (118) (seeFIG. 19).

With reference to FIG. 2, the air under pressure to cavity (123) on theleft side of the machine is preferably separately regulated from the airpressure entering cavity (123) on the right hand side of the machine,and if this is not done, instability may result. The correct pressuresfor the two cavities (123) are selected experimentally using twopressure regulators (1232) and (1233) (FIG. 2.) The two pressures areadjusted to achieve maximum stability.

The end plate (119) is attached to the shaft (102) by threads. The innersurface of shaft (102) is threaded along surface (126) and the outersurface of the ring attached to end plate (119) is threaded on its outersurface (127). The mating threads between the inner surface of shaft(102) and the outer surface (127), hold the end plate (119) to the shaft(102).

The current to pressure transducer (142) (FIG. 5) may be FairchildSeries T5100 manufactured by Fairchild Industrial Products Division,1501 Fairchild Drive, Winston-Salem, N.C. Preferably this apparatus iscatalog number T5120-1 having an input impedance of 2,340 ohms and aninput range of 1 to milliamperes. This transducer controls the airpressure to inlet (114) and holds that pressure at approximately 40 lbs.per square inch as previously explained.

Tapped holes, such as (128), may be placed in the ends of plates (119).Set screws may be inserted (or omitted) in these holes. The size andplacement of the set screws may be selected to perfectly balance therotating mechanism mechanically.

FIG. 19 is an exploded view of the details of the manifold (112), thebronze porous plate (124) and the end plate (125) of the turbine (118).

FIG. 20 illustrates certain details of caps (110) (FIG. 2). There aretwo of these caps (110), one at each end of the rotating apparatus ofFIG. 2. While only the details of the left cap (110) are shown in FIG.20, it is understood that the right hand cap (110) (FIG. 2) has similardetails. The cap (110) has a borehole (1100) through which bolt (1101)passes to fasten the cap (110) securely to housing (101).

One desirable feature, shown in FIG. 20, is that there are air bleedholes (1110) extending from vent (111) to the ambient atmosphere to thusallow an escape of air that passed the outermost seals (107) into vent(111).

FIG. 3 shows the supporting mechanism for the apparatus shown in FIG. 2and also moves the apparatus shown in FIG. 2 laterally for the purposeof providing the lateral component of the scanning motion. The scanningmotion obviously has, in addition to the lateral movement, a rotatingmovement which has already been described. The housing (101) originallyexplained in connection with FIG. 2 and which is also shown in FIG. 3 issupported by the cradle (130). The cradle (130) is mounted on thePneumo-Linear slide (131). This slide (131) is manufactured by PneumoPrecision, Inc., Precision Park, Keene, N.H., and, together with itssupporting rail (132), is an established and well known supportingelement. The slide (131) is supported, by air pressure, from the railing(132) which is also manufactured by said Pneumo Precision, Inc., asaforesaid.

In other words, the stationary rail (132) supports the slide (131), andthe support function between (131) and (132) is by means of airpressure. The slide (131), in turn, supports the cradle (130) which inturn supports the housing (101).

Running parallel to, and along side of, the supporting element (131),and the rail (132), is a lead screw (133) which is supported by threebearings (134) and which is prevented from unwanted lateral movement bycollar (135) which preloads two bearings (134) against each other. Thelead screw (133) is rotated by stepping motor (136) which is connectedto the lead screw (133) by the coupler (137).

The stepping motor (136) (FIG. 3) may be model M83-62 seriesmotor/driver manufactured by Compumotor Corporation, 1310 Ross Street,Petaluma, Calif. This stepping motor (136) has 25,000 steps perrevolution, and a preferred speed of approximately 1 revolution persecond. Using a 10 pitch lead screw (133), the apparatus of FIG. 2 scansapproximately 1,000 lines per inch during reading and/or writing.Following the scanning of a complete page, the stepping motor runs inreverse at a speed of approximately 6 revolutions per second in order toreturn the apparatus of FIG. 2 to its starting position for a new scan.

The stepping motor of 136 is a specie of the form of motors known assynchronous motors. With a synchronous motor it is possible to determineelectrically the exact lateral position of the scanning system (FIG. 2)at any given time.

The preferred speed for the turbine (118) is 6,000 rpm whereby themirrors rotate at that speed during scanning.

FIG. 4 is a top view of FIG. 3. In FIG. 4 the stepping motor (136)drives the coupler (137) which in turn drives the lead screw (133) whichcooperates with the lead screw nut (138) (FIG. 3) which is held in fixedrelation to the apparatus of FIG. 2 by bracket (139). The lead screwbearings are supported by support blocks (140) and (141). The bracket(139) is firmly attached to the support (131) which is carried by therail (132) by air pressure as explained heretofore. The apparatus ofFIGS. 3 and 4 rests on base (1400).

FIG. 5 is another view of the device of FIG. 2 showing certainadditional details. A laser beam (145) is shown entering the left end ofthe apparatus where it is focused by the lens (122) onto the mirror(121), and as the mirror rotates about the axis (109) (FIG. 2), thelaser beam is reflected to provide scanning. This beam intermittentlyand periodically passes encoding device (143) which reflects one signalpulse for each revolution of the mirror (121). The pulses may be usedfor counting, synchronizing or the like. The light reflective encoder(143) is supported by bracket (144) from the cradle (130) which is morefully shown and explained in connection with FIG. 3.

FIG. 6 shows a transport (150) for transporting the material which is tobe read (usually one full page), or the laser plate upon which writingwill occur, into the drum of the machine as will subsequently be morefully explained. The transport (150) is basically a sheet of epoxyglass, NEMA G-10 manufactured by various companies includingWestinghouse Corporation. Such a sheet is flexible so it can follow theinner curved surface of the drum (243), shown in FIG. 1. The sheet (150)has metal strips (151) and (152) along its forward and rear endsrespectively. The forward strip (151) has indents (153) for the purposeof coarse registration, as hereafter will be explained. The entiredevice of FIG. 6 moves into the read/write drum (243) (FIG. 1) along thedirection of arrow (154). For precise registration purposes there is ametal strip (155) having a registration hole (156) near its right endand a registration slot (157) near its left end. Registration pins (261)are used to align the transport.

Separate registration pins (159), for locating printing plates andpaste-ups, project upwardly from the flexible plate (150). The detailsof the pins (159) are shown in FIG. 7. Each pin (159) has a metal baseportion (160) and a metal washer (161) to hold it in place.

A number of strips (162) of polyurethane tape define the areas for thereading and writing materials. Strips (162) serve basically as a vacuumbarrier for the material, on which reading or writing is to beundertaken. Such material will be sealed in place on the sheet (150).

Assuming that there is a page of material, which is to be converted intoa printing plate, it would be placed in the reading section, which wouldnormally be the left-hand rectangular section of FIG. 6, bounded by tape(162). After the material to be read has been positioned as aforesaid, asheet of Plexiglas (163) (FIG. 8) is applied on top of the material.This sheet of Plexiglas (163) has clearance holes (164) which areslightly larger than the registration holes (159) to make sure that thepiece of Plexiglas (163) covers the material to be read.

The strip of tape (165) acts as a hinge and enables the Plexiglas sheet(163) to be opened like a book for the insertion or removal of materialto be read. At the right edge of the Plexiglas sheet (163) there is aflap (166) with hinge (175) which is securely bonded, or otherwisefixed, to the glass epoxy sheet (150) but is not bonded or sealed to thePlexiglas sheet (163) and therefore constitutes a flap which may be usedto cover the right edge of the Plexiglas sheet (163). The Plexiglassheet (163) is, of course, transparent and non-polarized so that readingmay take place through it. The flap (166) has slits (167) to preventbuckling when the epoxy glass sheet (150) moves into a curved positionas will appear later. The flaps provide restraint to hold the materialsagainst the transport (150) as it curves into the drum (243).

FIG. 9 illustrates a detail of the right hand section which is used tohold the output material (such as a printing plate or lasermask) onwhich writing may take place. The strips of tape (162) serve the samefunction for the (writing) right hand rectangle as they did for thereading (left hand) rectangle. They are covered by a flap (168) which issecured to the epoxy sheet (150) by tape (169). Slits (170) are providedto prevent buckling. These flaps also provide restraint to thematerials.

A flexible thin aluminum plate is positioned on the epoxy sheet (150)beneath the output material and held along its left edge by flap (168).Its right edge is held by flap (171).

Flap (171) is hinged by a piece of tape (172) so that the flap may beraised out of the way to position the aluminum plate and the outputmaterial as desired. When the aluminum plate and the output materialhave been placed in position and their left and right hand edges coveredby flaps (168) and (171), respectively, the transport sheet (150), andthe elements held by that sheet, are ready for movement into positionfor reading and writing.

The details of the lower right hand corner of the Plexiglas sheet (163)and its covering are shown in FIG. 11, where the strip of tape (162)forms the outer limits of the material to be read and the Plexiglassheet (163) is shown extending on top of tape (162). Two strips of tape(174) applied over the top of strip (162) are added so that all threestrips of tape (162) and (174) equal the thickness of the Plexiglassheet (163). The flap (166) is placed on top of tape (174) and is heldin place by the strip of tape (175) which permits strip (166) to behinged and, thus, be readily removable from, or placed onto, the top ofPlexiglas sheet (163).

The details of the lower left hand corner of the Plexiglas sheet (163),are shown in FIG. 12 where the strip of tape (162) overlaps sheet (150).The sheet of Plexiglas (163) overlaps the tape (162) and is hinged tothe sheet (150) by the strip of tape (165).

A magnet (176) is located on the strip (151) to enable the position ofthe apparatus to be sensed. This magnet is used for control purposes aswill be explained later.

A limited portion of the right hand end of strip (152), namely portion(177), is thinner than the remaining portion of strip (152) because itis engaged by a pinch roller for driving the sheet (150) into position.

In like manner, a limited portion (178) of the right hand end of strip(151), a limited portion (179) of registration strip (155), a limitedportion (180) at the left end of strip (151) and a limited portion (181)of strip (152) are also made thinner than the remainder of the strips towhich they are connected for reasons similar to that described inconnection with the thin portion (177).

Two identical transports (150) of the type shown in FIGS. 6 and 8 arenormally used. The one which is first fed into the drum (243) willhereafter be called the first transport (150), and the other one will becalled the second transport.

FIGS. 13, 14, 15 and 16 show the table on which the transport (150) ofFIG. 6 is mounted prior to transport (150) being fed into the machinefor reading or writing. These FIGS. 13 to 16 show a frame (190) and thebed (191) of the table. Near the rear end of the bed (191) of the tableis a bar (192) which has a normal (rear) position shown in full linesand a forward position shown in dotted lines. The rear end of metalstrip (152) of the transport (150) (FIG. 6) is placed on the tabledirectly in front of bar (192) when the latter is in its rear(full-line) position. The overall width of the transport (150) (FIG. 6)is slightly smaller than the distance between the vertical members (193)and (194) of the brackets (195) and (197). The upper ends of thevertical members (193) and (194) are pivoted at (196) and (198)respectively. The length of transport (150), including strips (152) and(153) is slightly less than the lengths of brackets (195) and (197).

There are four air cylinders (200) which always operate in synchronismto either raise or lower the table by about 1 inch. When there is airpressure in the upper section of the four cylinders (200), the table bed(191) is in its lower position and when air pressure is applied to thefour cylinders (200) in the lower section, the air pressure moves thetable bed (191) to an upper position about 1 inch above the lowerposition.

When the table (191) has been raised to its upper position aforesaid,the plane of a transport (150) resting directly on bed (191) nowcoincides with the horizontal tangent of the pinch rollers (201, 202,203 and 204). Rollers (202) and (204) are idle rollers which normallycontact rollers (201) and (203) respectively. It is the horizontaltangent of the rollers, where the idle rollers contact the drive rollers(201) and (203), that is in the same plane as the transport (150), whenthe latter is resting on bed (191).

A motor (205) drives timing pulley (206) which in turn drives timingbelt (207) which, in turn, rotates the driving rollers (201) and (203).The idling rollers (202) and (204) are driven by reason of their contactwith rollers (201) and (203).

If we assume that the first transport (150), such as is shown in FIG. 6,is resting in its normal position on bed (191) with the rear edge ofstrip 152 (FIG. 6) in contact with a forward end of the bar (192) whenthe latter is in its rear position (solid lines), the apparatus is nowready to push the first transport toward the drum (243) for purposes forreading and/or writing.

Air cylinder (210), when air pressure is applied to it, causes bar (192)to move forwardly from its rear (solid line) position (FIG. 13) to itsdotted line or forward position. When this bar moves forward, it pressesthe metal strip (152) (located at the rear end of the transport (150) ofFIG. 6), forwardly, causing the forward end (151) of the first transport(150), to move into a position where the thin ends of strip (151) arepinched between the pairs of rollers. That is to say the thin left end(180) of strip (151) moves between and is pinched between drive roller(201) and idle roller (202); and at the same time the thin right portion(178) of strip (141) moves between and is pinched between idle roller(204) and drive roller (203). Since the drive rollers (201) and (203)are driven by motor (205), the transport (150) continues to moveforwardly into the drum (243) of the cylinder. Completion of the loadingof the transport (150) will be described later.

After the first transport (150), described above, was fed into themachine, the operator may have loaded a second transport (150) so thatit may also be fed into the machine as soon as the first transport (150)has been scanned and returned from the drum (243). In order toaccomplish this result the operator has laid the second transport (150)on the shelves (211) and (212) of brackets (195) and (197) respectively.As soon as the first transport (150) has registered into drum (243),sensors (not shown) sense that action and automatically apply pressureto cylinders (213) and (214) to thereby cause arms (215) and (216),which are respectively connected to brackets (195) and (197), to rotatethe brackets (195) and (197) about the pivots (196) and (198)respectively. Since the bracket (195) rotates clockwise, and the bracket(197) rotates counterclockwise, the second transport (150), which is nowpositioned on the brackets (195) and (197), will fall due to gravityonto the bed (191) of the table. Guides (217) and (218) are mounted onthe upper surface of bed (191) and guides the second transport (150)after it has dropped by reason of gravity from the brackets (195) and(197). Guides (217) and (218) run the entire length of the bed (191) andare, of course, located on the bed (191) underneath the brackets (195)and (197), as shown in FIG. 14.

After the first transport (150) has been fed into the drum for scanning,and the second transport (150) has been dropped from brackets (195) and(197), onto the table (191), the brackets (195) and (197) are now readyto receive the first transport (150) after it has been scanned.

To prepare the apparatus for this function, the air is allowed to escapefrom cylinders (200) and the table bed (191) is lowered by 1 inch so thehorizontal shelves (211) and (212) are at the same level as thehorizontal plane that is the tangent of rollers (201) and (202) at thepoint of contact between those rollers. The first transport (150) thatis returning from the drum (243) is therefore, at the same level as theshelves (211) and (212) and, since the motor (205) has been reversed,the rollers are driving the first transport (150) toward the rear of thebrackets (195) and (197). This action continues until the firsttransport (150) has been driven as far rearwardly as the rollers (201)to (204) can drive it.

As the first transport (150) is being moved rearwardly, the upper sideof it is engaged by brushes (219) for the purpose of firmly holding thefirst transport (150) against the upper surface of shelves (211) and(212). When the first transport (150) clears rollers (201-204), itsstrip (152) is moved more rearwardly than arms (220) and (221), whicharms are respectively pivoted at (222)and (223). Next, the arms (220)and (221) are rotated about pivots (222) and (223) until the arms (220)and (221) contact the epoxy glass portion of the first transport (150).The arms (220) and (221) are then translated rearwardly, thereby causingthe first transport (150) to move to a position where the rear edge ofstrip (152) (FIG. 6) is above the forward edge of bar (192), it beingnoted that this bar has been moved to its most rearward (solid line)position since the air pressure has been removed from cylinder (210).

It will be recalled that the second of the two transports (150) has beendropped onto the table bed (191), where it has remained while the firsttransport (150) has been scanned and returned. The second transport(150) is now fed into the scanning drum (243) by means of bar (192),rollers (201-204), etc., the same as was done for the first transport(150). Pressure may now be applied to cylinders (213) and (214) to causethe first transport (150) to fall on bed (191). The operator may nowreplace the paste-up or other material to be printed from the left handsection of the first transport (150), and similarly he or she places newoutput material into the right hand section of the first transport(150).

In order to provide the rotary and transitory motion of arms (220) and(221), there are provided two Stilson Miniature Rota-Clamps. The firstof these Rota-Clamps comprise a housing (226) and a shaft (227). Thehousing (226) is supported by a frame (230) which is part of the bracket(195). The Stilson Miniature Rota-Clamp (226), (227) is so arranged thatwhen the forward end of shaft (227) is pressed rearwardly, by the aircylinder (224), the arm (220) first rotates until it contacts the firsttransport (150), and then it translates rearwardly until it moves thefirst transport (150) to its ultimate final position above the edge ofbar (192). The Stilson Rota-Clamp (228, 229) is held in position byframe (231) of the bracket (197). The second Stilson Rota-Clamp (229) ismounted on bracket (197) and when air pressure is applied to cylinder(225), it first , causes rotation of arm (221) and then providestranslation of arm (221) to move the first transport (150) rearwardly toits final position. Air pressure is normally applied to cylinders (224)and (225) simultaneously to thus cause arms (220) and (221) to act inunison in moving the first transport (150) rearwardly.

As stated earlier when the first transport (150) was on the brackets(195) and (197), the second transport (150) was being fed into scanningposition. To do this air pressure was fed into cylinders (200) to raisebed (191). Bar (192) was moved forwardly, rollers (201 to 204) wererotated and all other steps performed in the sequence that was necessaryfor moving a transport into scanning position. Such steps were describedin connection with moving the first transport (150) into scanningposition. After the second transport (150) is fed into scanningposition, the first transport (150) is dropped from brackets (195) and(197) onto bed (191) so material can be loaded and it can be fed intodrum (243). The aforesaid procedure using the two transports (150) canbe repeated over and over to form all of the pages of a newspaper.

The bracket (195) is pivoted about shaft (196) which in turn issupported by support elements (235) at both the front and rear ends ofthe machine. Similarly supports (236) support shaft (198) which carriesbracket (197).

The drum (243), which is fed with a transport (150), is bounded by awall (237) which has an opening (238), covered by a door (239), pivotedat (240). The purpose of the door (239) is to prevent the laser beamfrom exiting from the drum and injuring the personnel, such as byentering the eyes of the operator. Whenever a transport (150) is beingfed to or from the drum, the door (239) is open. Whenever the door (239)is open, a mercury switch operated by rotation of the shaft (240) of thedoor deenergizes a solenoid to move a shield (not shown) to a positionwhich prevents the laser beam from being directed toward the opening(238). When a transport (150) is not entering or leaving this drum(243), the door (239) is closed and this prevents the laser beam frominjuring the operator.

FIG. 17 illustrates the drum (243) and the apparatus of the left end ofthe drum for processing a transport (150). The ramp (249) has anupstanding flange (250), at each side thereof, to guide the transportinto the the correct position as it enters the drum (243). As thetransport (150) enters the drum (243), the magnet (176) (FIG. 6) on thetransport (150) passes across sensor (257) which senses the presence ofthe magnet and thereupon actuates an electrical circuit which in turnapplies air pressure to cylinder (258) which in turn causes shoulderscrew (259) to be moved upwardly. Since the side walls of the left handslot (153) in the forward strip (151) of the transport (150) (FIG. 6)have straddled the shaft (263), it is apparent that when the head (259)of the shoulder screw moves upwardly, it clamps the left end of strip(151) (see FIG. 6) to the disc (251) (FIG. 17). Since there is a similarshoulder screw and air cylinder on the right hand side of the drum(243), which cooperates with the slot (153) at the right end oftransport (150), there will be two shoulder screws (259) clamping thestrip (151) to rotatable discs such as (251). When the sensor (257)sensed the magnet (176), it not only energized the circuit (2571) whichcaused air pressure to be applied to cylinder (258), but it alsoenergized a circuit starting a motor (2520) having a shaft (252)connected to a gear (253) which is mated with another gear (254) on disc(251), and thereby caused the disc (251) to start rotating. In view ofthe fact that the strip (151) of the transport (150) has been clamped(by shoulder screw head (259)) to the disc (251), the rotation of discwill continue to move transport (150) along slot (264) until thetransport (150) has reached its final position, as will hereafter bedescribed.

Shortly after the disc (251) begins to rotate, the pin (261) engagesregistration hole (157) (FIG. 6) and thereby, ensures that the transportwill be coarsely registered with the inside surface of the drum (243).In its final position, the pin (261) is not only passing through theslot (157) but is in alignment with hole (262) in the drum (243),whereupon air pressure is applied to cylinder (260) to press pin (261)through the hole (157) and into the hole (262) in order to hold thetransport (150) and disc (251) in precise position during scanning. Thedisc (251) is supported by rollers (256) which insures that it rotateswith respect to the drum (243) axis.

Suitable means can be provided for automatically stopping the disc (251)when the pin (261) is in alignment with the hole (262). Such means may,for example, include a magnet (2510) on the disc (251). This magnet willbe sensed by sensor (2511) when the disc (251) is rotated to theposition where pin (261) is facing hole (262). An electrical circuit(2512) is provided for deenergizing the motor (2520) and thus, stoppingmotor shaft (252) in a position where pin (261) registers with hole(262). Circuit (2512) applies current to valve (2513) to admit air tocylinder (260) to move pin (261) into hole (262).

It is understood that the disc (251), bearings (256), cylinders (258)and (260), shoulder screw (259) and registering pin (261), together withhole (262), are located along the left hand margin of the transport(150), within the drum, for the purpose of driving and registering ofthe left hand portion of the transport (150). Similar devices arelocated at the right hand side of drum (243) to perform the samefunction along the right hand margin of transport (150).

FIG. 18 is a sectional view of the drum showing the vacuum system and isa view from the right hand side, as distinguished from FIG. 17 which isa view from the left hand side.

In FIG. 18, the transport (150) is shown in its final position withstrip (151) at its forward end and strip (152) at its rear end. It isfurther assumed that the transport (150) has been moved to its finallocation within the drum (243) and that the registering pin (261) hasentered hole (262) as described in connection to FIG. 17.

The transport (150) has holes (265) extending completely through theepoxy glass sheet (150) and located just below the upper piece of tape(162) for sealing the output material.

The aluminum plate which is used for making a printing plate extendsfrom the lower piece of tape (162) (FIG. 6) to the lower edge of theholes (265). Therefore, there is a space between the upper end of thealuminum plate and the lower end of the upper strip of tape (162); andthe holes (265) communicate with that space and are in alignment withthe groove (266) which runs across the drum (243) parallel to the axisthereof. The groove (266) is connected, by tubing, to a solenoid valve(267) which is in turn connected to one input of vacuum pump (248). Thepump has two separate inputs.

The output material (not shown) extends the complete distance from theupper edge of the lower strip of tape (162) to the lower edge of theupper strip of tape (162), so that it covers the air space between theupper edge of the aluminum plate and the lower edge of the forward stripof tape (162). The vacuum created in groove (266) and extending throughthe holes (265), therefore, sucks the output material toward the epoxyglass plate (150) around the entire periphery of the output material.The output material is held in position along its right and left handsides, until vacuum is applied, by the flaps (168) and (171) (FIG. 8).In this respect, see also FIG. 10.

The two solenoid valves (267) and (268) have an input electrical circuitconnected to control wire (2512) (FIG. 17) which causes these solenoidvalves to open when the pin (261) is registered in the hole (262) asaforesaid.

Grooves (269) and (270) run across drum (243) and apply vacuum to theupper part of the transport (150) to hold it firmly against the insidewall of drum (243). The vacuum for grooves (269) and (270) comes fromthe second input of the pump (248).

After the pin (261) has registered with hole (262) as aforesaid, thefollowing series of events happens. The cam (271), when it is normallyat an angular position 180° from that shown, is not actuating either ofthe switches (272) or (273). The squeegee roller (274) is shown in itsinward position, as shown in (274A). When the pin (261) has moved to theposition of registration with hole (262), circuit (2512) is actuatedwhich not only energized solenoids (267) and (268) but also startedmotor (2710) for rotating the cam (271) clockwise. The squeegee roller(274) then moves outwardly into contact with the transport (150), underthe force of air pressure fed into cylinder (275). As the cam (271)rotates clockwise, the squeegee roller (274) similarly swings clockwiseuntil it reaches the position (274B). Since the cam rotates clockwise,it first actuates switch (272) which energizes solenoid valve (276) toallow vacuum to be applied to grooves (277) and (278); thus, suckinganother section of the transport (150) inwardly towards the inner wallof (243).

As the cam (271) rotates further in the clockwise direction, itenergizes switch (273) which energizes solenoid valve (279) and appliesvacuum to grooves (280) and (281). Like the other grooves, each ofgrooves (277, 278, 280 and 281) run across the drum (243) parallel tothe axis thereof, and when vacuum is applied thereto, the transport(150) is sucked against the inner wall of the drum (243). As the cam(271) was rotating by about 160°, the squeegee roller (274) has beenheld against the inner wall of the transport (150) and has appliedpressure to press the transport (150) against the inner wall of the drum(243), to thus iron out any bubbles or other irregularities in thepositioning of the transport (150) within the drum (243).

It is noted that the suction through grooves (266, 269 and 270) isapplied as soon as the pin (261) registers with hole (262). At about thesame time that the vacuum is applied to those grooves, the squeegee(274) is extended, and cam (271) and squeegee (274) begin rotatingclockwise to, first move the cam into position, and secondly start thesqueegee pressing the transport against the inner wall of (243). Thesqueegee is so positioned with respect to the switches (272) and (273)that the squeegee passes over the portion of the transport (150) that iscovered by vacuum grooves (270) and (278) before suction is applied tothose grooves. Similarly, the squeegee (274) passes over the portion oftransport (150) that is covered by grooves (280) and (281) before thevacuum is applied to those grooves.

After scanning has been completed, the air pressure to cylinder (275) isreversed and the squeegee (274) retracts. The solenoid valves (267, 268,276 and 279) are then deenergized, and pin (261) is retracted from hole(262) by cutting off the air pressure to cylinder (260). The transport(150) is now free to be removed from the drum (243). The motor (2520)which is controlling disc (251) is then reversed and the transport (150)is then ejected from the drum (243) along ramp (249). Once the transport(150) has reached the point where its rear strip (152) has reached thepinch rollers (201 to 204), those rollers then cause the transport (150)to continually move outwardly onto the brackets (195 and 197) (FIG. 13)until the strip (152) has passed the arms (220) and (221). Thereafter,application of air pressure to cylinders (244) and (225) cause the arms(220) and (221) to not only rotate, but also translate, and move thetransport (150) along the brackets (195 and 197) to its normal startingposition ahead of the front end of bar (192). Then that transport (150)is allowed to drop onto bed (191), as aforesaid.

The overall operation will now be stated:

Let it be assumed that two printing plates for two pages of a newspaperare to be prepared. The paste-up for the first page would be placed inthe left hand section of the first transport (150) of FIG. 6. Analuminum plate together with an output material would be applied to theright hand section of said first transport (150) (FIG. 6) as aforesaid.This transport (150) would then be placed on the bed (191) of the table(FIG. 13) between the guides (217) and (218). The bar (192) would be inits rearward position and the rear end of strip (152) would bepositioned against the forward face of the bar (192). The bar (192) isthen moved forwardly pressing the first transport (150) into the rollers(201 to 204) which pinch the forward sections (181) and (178) of the bar(151), and cause the first transport (150) to move forwardly into thedrum (243). The door (239) is then opened and at the same time a shieldis moved into a position to prevent the laser beam from passing theopening (238). The rollers (201 to 204), acting upon the right and leftedges of the transport (150) continues to push the first transport (150)forwardly until grooves (153) engaged the shoulder screw (159). At thesame time that the aforesaid engagement occurs the magnet (176) issensed by sensor (257) which causes air pressure to be applied tocylinder (258) to thus clamp the leading edge of strip (151) to the disc(251). The disc (251) then rotates until pin (261) registers with hole(262). The first transport (150) has now been rotated to its scanningposition. Air pressure is then applied to cylinder (260) to cause thepin (261) to engage hole (262) and maintain the first transport (150) inits scanning position. At this point, the cylinder (258) is now locatedin its dotted line position. The air pressure applied to opening (114)rotates the turbine (118) which in turn rotates the shaft (102) and itsheads (120). This accomplishes the rotating component of the scanning.The horizontal component of the scanning is accomplished by steppingmotor (126) rotating the lead screw (133).

As a result, the reading and writing sections of the first transport(150) are scanned. While all of this has been taking place, the operatorhas applied the second page of paste-up material in the left handsection of the second transport (150) (FIG. 6) and has provided a newoutput material in right hand section of FIG. 6. The control system thenreleases air pressure from cylinders (200) causing the horizontalportions (211) and (212) of brackets (195) and (197) to move intoalignment with the rollers (201 to 204). As the disc (251) (FIG. 17)rotates in the counterclockwise direction to the first transport (150),which has now been fully scanned, that transport (150) moves outwardlyonto the brackets (195) and (197). Pushers (220 and 221) are activatedto push the transport (150) away from the rollers. Air pressure is thenapplied to cylinders (200) to raise the bed (191) so that the secondtransport (150) may now move forward through the pinch rollers (201 to204) in the same manner as was described in connection with the firsttransport (150). The first transport (150) is now dropped onto the bed(191), then reloaded with the third page of the newspaper to make roomfor the second transport (150) to return along the brackets (195) and(197). The first transport is now ready to be fed into the drum (243) asecond time. This process is repeated until printing plates for theentire newspaper have been prepared.

The writing operation, which can be used to prepare any number ofprinting plates, is well known prior art. Alternatively, the writinglaser may prepare the printing plate directly in accordance with otherprior art teachings.

There are two holes (1110) (FIG. 20) extending from slot (111) to theexternal atmosphere, but not along a line which will intercept one ofthe holes for the bolts (1101). The vent holes (1110) occur on both endsof the device, and also avoid instability in the operation of the shaft.

Having described the various parts of the invention, it may be helpful,in understanding the requirements of the control system for the machine,to set forth the steps required in order to operate the machine throughone complete cycle. These steps are as follows:

1. Apply pressure to cylinders (200) to raise bed (191).

2. Apply pressure to cylinder (210) to push bar (192) forward.

3. Start motor (205) to cause rollers to move transport (150) into drum(243). Door (239) is also opened.

4. Sensor (257) senses magnet (176) which admits pressure into cylinder(258) to cause head (259) to clamp strip (151) of transport (150). Thesensing of magnet (176) also starts a motor (2520) which rotates shaft(252) which in turn rotates disc (251) clockwise.

5. A sensor (2511) next senses when pin (261) is in alignment with holes(262), and applies air pressure to cylinder (260) to press pin (261)into hole (262). The door (239) is closed.

6. Air pressure is applied to cylinder (275) to move squeegee (274)outwardly and into contact with sheet (150).

7. Cam (271) rotates clockwise along with squeegee (274).

8. Vacuum solenoid valves (267) and (268) are energized simultaneously,but valve (276) is not energized until squeegee has passed grooves (277)and (278), and valve (279) is not energized until squeegee has passedgrooves (280) and (281).

9. Immediately after step 5, air pressure is applied to cylinders (213)and (214) to rotate brackets (195) and (197) to drop second transport(150) on bed (191).

10. Air pressure is removed from cylinders (200) so that bed (191) oftable is lowered. The operator may now load the materials.

11. Scanning is performed.

12. Squeegee (274) is retracted and rotated clockwise until it is in itsoriginal position.

13. Solenoid valves (267, 278, 276 and 279) are deenergized. Airpressure is exhausted from cylinder (258) so pin (261) is removed fromhole (262). The motor which rotates shaft (252) is reversed andtransport (150) is driven out of drum (243). The door (239) is opened.

14. Rollers (201 to 204) are driven in reverse by motor (205) to drivefirst transport (150) out of drum (243) onto brackets (195) and (197).Pushers (220) and (221) are activated to push transport (150) off ofrollers.

15. Air pressure is applied to cylinders (200) to raise platform sosecond transport (150) is in alignment with rollers (201 to 204).

16-24. Steps 2 to 10 are now performed on the second transport (150).

25-26. After second transport (150) is scanned, steps 12 through 14 areperformed on second transport (150) to eject it from drum (243) and ontobrackets (195) and (197), etc.

The above 26 steps performed one complete cycle of operation. Thosesteps are repeated until printing plates for all pages of the newspaperhave been made.

The aforesaid 26 steps may be performed in any of various ways. One waywould be to have a push button for each step. These buttons could bedepressed in the desired sequence. A second way performing the sequenceis to employ a rotary stepping switch which continuously rotates andcloses a circuit to perform one of said steps each time the switchadvances one step.

Even if hand push buttons, or a stepping switch, is provided to controlthe system, some of the operations can be performed automatically. Forexample, circuits (2512) and (2571) automatically perform two of the 26steps.

Another way of performing the 26 steps, in the desired sequence, is witha suitably programmed microprocessor, or other solid state device.Suitable microprocessors are described in the book entitled: "PracticalHardware Details for 8080, 8085, Z80 and 6800 Microprocessor Systems,"by James W. Coffron, Prentice Hall, Inc. (1981).

We claim to have invented:
 1. In a scanning system,a transport having alower face, and an upper face for holding the material to be scanned, abase upon which the transport may rest while said material is beingscanned, said base having depressed areas spaced along one dimension ofsaid transport, said depressed areas forming cavities bounded by thetransport and said base, and means for evacuating said cavities, with atleast some of the cavities along said dimension being progressivelyevacuated, one after another as the distance along said dimension fromone end of the transport increases, to thereby securely hold thetransport in place on said base during scanning.
 2. In a scanning systemas defined in claim 1,a squeegee roller, and means for passing saidsqueegee roller over the upper face of the transport along saiddimension, with the squeegee roller passing above at least one of saiddepressed areas after it has been evacuated.
 3. In a scanning system asdefined in claim 1,said transport having at least one hole through itextending upwardly from said lower face to said upper face, said holecommunicating with at least one of said depressed areas, wherebymaterial to be scanned placed over said holes, on said upper face, willbe held securely in place by suction.
 4. In a scanning system:a scanninghead which rotates about an axis and translates along said axis, a basedefining a curved inner wall of said scanning system, each cross-sectionof said curved inner wall which is perpendicular to said axis formingthe arc of a circle of given diameter whose center is on said axis, atransport having an upper face for receiving the material to be scanned,and a lower face which may be held in place on said base; said transportbeing made of material sufficiently flexible that said lower face mayconform to the configuration of said curved inner wall, said inner wallhaving depressed areas at different angular positions along said arc,and means for evacuating said depressed areas with at least some of saiddepressed areas being evacuated progressively, one after another, as theangular position along the said arc increases.
 5. In a scanning systemas defined in claim 4:said transport having at least one holetherethrough perpendicular to said faces, and communicating with atleast one of said depressed areas for applying suction to material to bescanned, positioned on said upper face; whereby to hold such material inplace.
 6. In a scanning system as defined in claim 4,a squeegee rollermounted for rotation about said axis, and means for moving said squeegeeroller across the upper face of said transport, said squeegee rollerapplying pressure to one given portion of the upper face of thetransport only before the corresponding lower face of the transport isheld by suction in said depressed areas against said inner wall.
 7. In ascanning system as defined in claim 6,said squeegee roller passing oneof the areas to which suction has been applied, before suction isapplied to other areas at greater angular positions along said arc. 8.The method of supporting a flexible transport having two faces, by acurved inner wall of a scanning system, comprising:moving said transportinto a position where one side of said transport is substantiallycontiguous with said curved inner side wall, and progressively applyingsuction along one dimension of said transport to hold the transportagainst said curved inner wall.
 9. The method of claim 7, whichcomprises applying pressure progressively along said dimension of saidtransport, said pressure being applied over at least a portion of thetransport, after said suction has been applied to that portion of thetransport, but before suction has been applied to other portions of thetransport to which pressure has not yet been applied.